Hello Surya,
I'm sorry that this is happening. Your best bet when you have hit a roadblock in Quickbase is to request assistance from the technical support team. If you click the question mark at the top of most screens in Quickbase, you'll see "Manage support cases" in blue on the menu that appears. This will take you to where you can create or update a case for support to have a look at your app. Be prepared for them to request admin level access into the application to research the issue directly. I hope this helps. I'm not sure why your sandbox is not allowing you to publish but hopefully support can get you back on track ASAP.
I did that before searching online. They say "Sadly there is no solution right now until the Dev team fixes it." I don't know how long it is going to take for them.
I posted this question and then continued to search online. I found one link similar to this issue. Guess what that was pointing to! This page!
